One‐Pot Synthesis of Block Copolymers by a Combination of Living Cationic and Controlled Radical Polymerization

• Published in: Macromolecular rapid communications. 2019-01, Vol.40 (1), p.e1800398-n/a
• Main Authors: Trützschler, Anne‐Kristin, Leiske, Meike N., Strumpf, Maria, Brendel, Johannes C., Schubert, Ulrich S.
• Format: Article
• Language: English
• Subjects: 2‐oxazoline; Acrylates; Addition polymerization; Block copolymers; Cationic polymerization; cationic ring‐opening polymerization; Cations - chemistry; Chemical synthesis; Copolymers; Free Radicals - chemistry; macro‐chain‐transfer agents; Molecular Structure; Oxazoles - chemical synthesis; Oxazoles - chemistry; Polymerization; Polymers; Purification; reversible addition–fragmentation chain‐transfer polymerization; Ring opening polymerization
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.201800398

The reversible addition–fragmentation chain‐transfer (RAFT) process represents a sophisticated polymerization technique for the preparation of tailored and well‐defined polymers from acrylates, acrylamides, and (meth)acrylates. The direct switching from other methods, such as cationic polymerizations, without the need for tedious functionalization and purification steps remains challenging. Within this study, it is demonstrated that poly(2‐oxazoline) (P(Ox)) macro chain‐transfer agents (macro‐CTAs) can be prepared through the quenching of the cationic ring‐opening polymerization with a carbonotrithioate salt. The end‐functionalization of the P(Ox)s is observed to be almost quantitative and the macro‐CTAs could be directly used for RAFT polymerization without further purification. This one‐pot procedure could be extended to a variety of (multi)block copolymers consisting of different 2‐oxazolines and acrylates with good‐to‐excellent control. Kinetic studies revealed the controlled polymerization of block copolymers, which are further accessible for α‐ and ω‐end‐functionalization. The simplicity and versatility of the approach promise a straightforward access to block copolymers from cationic and controlled radical polymerizations. The combinatory approach for the polymerization of cationic ring‐opening polymerization (CROP) of 2‐oxazolines and controlled radical polymerizable vinyl monomers is a promising route to applied polymers. Block copolymers up to tetrablock quarterpolymers can be synthesized using a carbonotrithioate salt for the combination of CROP and reversible addition–fragmentation chain‐transfer polymerization. Kinetic studies show a controlled polymerization behavior without intermitting purification.